Cryptographic key escrow

A non-transitory computer readable storage medium storing instructions that cause one or more processors of a client device to:

• receive from a target platform, a challenge responsive to a request to access the target platform;
• provide, to an escrow platform over a network, another request that comprises at least information based at least in part on the challenge received from the target platform;
• receive over the network, from the escrow platform in response to the other request, a digital signature calculated using a secret associated with the target platform and at least the information based at least in part on the challenge;
• provide to the target platform, at least the digital signature;
• and
• receive, after the target platform verifies the digital signature, an indication that access to the target platform was granted.

A system, comprising:

• an escrow platform comprising:
• one or more processors;
• and
• a memory comprising instructions that, upon execution, cause the escrow platform to:
• receive a request to sign a challenge over a network from a client device, the challenge generated by a target platform based on the client device requesting access to the target platform;
• generate, by the one or more processors of the escrow platform, authenticity information, the authenticity information calculated using a secret associated with the target platform and information based at least in part on the challenge;
• and
• provide at least the authenticity information over the network to the client device.